Sled pulling improves explosiveness, power, and your conditioning base.  Just about anything can be pulled, and there are an infinite number of ways to do it.  In the video, 2 hand pull, duck walk pull, and 2 hand press are shown.  Sled pulling and the variations that can be done carry over well to athletic performance and engage the entire body.  Good old fashioned work that increases leg drive and explosion off the start.  Pulls and pressess can be used to get the chest, back, and shoulders involved.  Increase the load to improve strength and lighter loads at a faster pace to work on your acceleration and conditioning.